JP2007297527A - Method and apparatus for electric power generating using waste material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new method and apparatus in which electric power is generated from waste materials. <P>SOLUTION: The dry distillation of waste materials is carried out using water vapor. Dry distilled gas and dry distillation residue (charcoal) are refined into hydrogen and a gas mainly comprising carbon monoxide by water gas reaction and activation with water vapor while the dust removal and washing are carried out, and are converted into a high quality gas fuel which can be used for a fuel cell, a gas engine, and a gas turbine and are used as a power generation fuel. On the other hand, the residue (charcoal) caught as a dust is activated with water vapor simultaneously with the water gas reaction to form a high quality activated charcoal. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  This invention is an organic waste, such as food residue, food sludge, human waste / sewage sludge, feces, plastic, waste paper, wood waste, etc., or mixed waste containing them, and pyrolysis generated from them. The present invention relates to a method and an apparatus for generating gas and residue (charcoal) as fuel and generating electric power using this fuel.

  Conventionally, for power generation using waste, a method of generating power using combustion heat generated when the waste is burned and incinerated has been employed. However, in recent years, the generation of dioxins by combustion incineration has become a social problem, and the development of gasification power generation of waste as a method to replace combustion incineration is being promoted. There are the following two methods for power generation by waste gasification (dry distillation).

1. 1. Method using dry distillation gas as a gas fuel as it is Method of cooling dry distillation gas and using it as liquid fuel Method of using dry distillation gas as gas fuel as it is
Organic wastes and mixtures contain chlorine, and naturally the carbonization gas recovered from these wastes also contains hydrogen chloride. In addition, since the carbonization gas contains carbonization residue (charcoal) and oil (tar content), they are naturally included in the recovered gas fuel.

Further, when air enters when waste is introduced or equipment leaks, oxygen is contained in the dry distillation gas, that is, the dry distillation gas becomes an explosive gas mixture, and there is a risk of explosion.
At present, it is possible to remove hydrogen chloride and charcoal contained in the recovered gas fuel, but there is no method for removing oil (tar) and oxygen, and there is no power generation device that uses the recovered gas fuel.

2. Method of cooling dry distillation gas and using it as liquid fuel Like the case of using dry distillation gas as gas fuel as it is, liquid fuel contains hydrogen chloride and charcoal, but there is no way to remove them, and recovered liquid fuel There is no power generator that can be used.

  Due to the problems 1 and 2, the dry distillation gas is not liquefied but incinerated in a gas combustion furnace as it is, and only the dry distillation residue (charcoal) is recovered.

  However, as mentioned above, carbonization gas contains residues (charcoal) and oil. Therefore, when incinerating dry distillation gas in a gas combustion furnace, charcoal and oil contained therein are combusted together, and there is a risk that new dioxins will be generated in this furnace. The law also regulates the combustion of dry distillation gas in a gas-fired furnace as the same incineration facility.

On the other hand, the collected residue (charcoal) can be used as a fuel, a soil conditioner, a water purification agent, a house moisture conditioner, or the like. However, in reality, there is little demand as a soil conditioner, water purification agent, house humidity control agent and the like. Even when used as fuel, the residue (charcoal) is a solid fuel, so its use is limited to thermal power plants, cement kiln furnaces, etc., and demand is low. For these reasons, most of the residue (charcoal) is landfilled as waste.
JP 2005-247930 A

  Due to environmental issues, diversification of energy, such as solar power generation and wind power generation, is required, and development of bio power generation and the like is being promoted in waste power generation. However, raw materials for bioelectric power generation are limited to those that can be rotted and fermented among organic wastes, and the installation site is greatly limited due to the vast site for rot and fermentation and the problem of odor. Therefore, the development of waste power generation that can deal with all wastes and the installation location is not limited.

  An object of the present invention is to provide a power generation method using waste that can meet the above-described demand and an apparatus for carrying out this method.

  In the power generation method according to the present invention, organic waste is safely dry-distilled using water vapor produced using exhaust heat.

Next, the temperature of the mixture of water vapor and dry distillation gas is raised to 900 ° C or higher. Thus, the entrained oil and charcoal are converted to CO and H ₂ by the water gas reaction shown in Chemical Formula 1.

Further, oxygen contained in the dry distillation gas is converted into CO ₂ and H ₂ O by the oxidation reaction shown in Chemical Formula 2 and Chemical Formula 3.

Furthermore, the residue (charcoal) after dry distillation is pulverized to 20 microns or less, and is converted into CO and H ₂ through the process shown in the same chemical formula 1 as the dry distillation gas.

  Further, the remaining residue (charcoal) is contained in the gas activated by water vapor, but this solid content is captured by the dust collector and taken out from the lower portion of the dust collector and reused as activated carbon. In addition, harmful gases such as hydrogen chloride gas are washed with caustic soda in a gas washing tower.

  Through the above steps, it is possible to obtain a high-quality gas fuel that can be used for fuel cells, gas engines, gas turbines, and the like.

  The waste power generation apparatus according to the present invention is composed of three apparatuses: a gas generation apparatus, a power generation apparatus, and an emergency diffusion tower.

  The gas generator includes a dry distillation chamber that raises the temperature of waste and gasifies it, and a high-temperature reaction tower that promotes a water gas reaction. Further, the inside of the high-temperature reaction chamber is filled with a pebble-like ceramic material having good heat conductivity as a reaction accelerator.

  The downstream of the high-temperature reaction tower is provided with a cooling tower for purifying gas and making it into gas fuel, a dust collector, a gas washing tower, and an induction fan for sending gas to the gas storage tank.

  The recovered gas fuel can be used as a heat source for dry distillation and reaction, and of course the same is true even after conversion to electricity.

  Leaking flammable gas outside the apparatus is dangerous, and it is necessary to operate the apparatus at a slight negative pressure. However, there is a risk that outside air may enter the device if it is in a non-pressure state. Air entering when waste is introduced, air contained in waste, air leaking from a device seal or the like. And it is inevitable to avoid such air intrusion.

  A flammable gas explosion does not occur if the air concentration is too high or too low.

  The explosion limits for combustible gases are usually expressed in the table below.

The explosion limit is greatly changed by the presence of an inert gas (inert gas), and the explosion limit is narrowed as the ratio of inert gas / combustible gas increases. Nitrogen / hydrogen = 16, carbon dioxide / hydrogen = 10, In the case of nitrogen / carbon monoxide = 4 and carbon dioxide / carbon monoxide = 2, the explosion limit becomes 0, and no matter how much air leaks, no explosion of combustible gas occurs. In addition, the inert gas explosion prevention capability is higher in the order of CO ₂ , H ₂ O, and N ₂ , the water vapor is between carbon dioxide and nitrogen, and the mixed gas of two or more flammable gases is Le Chaterier (Le Cha. Terier). ) Can be calculated from the following law.

  The present invention calculates the ratio of inert gas / flammable gas when the explosion limit of the component gas reaches 0 from the above-mentioned mixed gas law, and introduces a vapor amount more than twice this value in anticipation of the safety factor. It is characterized by avoiding the danger of combustion and explosion.

  In addition, for the purpose of avoiding a backfire from a fire type, a water seal drum having a gas-liquid separation function is provided in a pipe connected from the apparatus to a gas storage tank.

  In order to ensure stable electric power, it is preferable to provide a calorimeter, a gas flow meter, a mixer, and a gas flow rate control valve in a pipe that matches the generator. In other words, the components of the waste are unstable, and naturally the components of the recovered gas fuel and the amount of heat are also unstable. Therefore, it is desired to measure the total amount of heat with a calorimeter and a gas flow meter, and to control the amount of gas introduced into the generator with a gas flow rate control valve based on this. When the total heat quantity of the gas entering the power generation device is insufficient, it is necessary to automatically mix commercially available LPG or LNG gas and the generated gas with a mixer and introduce the gas into the generator.

  The emergency radiation tower is used to safely release gas to the atmosphere after combustion in the event of a disaster such as a fire or an earthquake, or during a power failure.

  Since the carbonization continues until the temperature of the waste in the apparatus drops even if the heat source is turned off, an emergency dispersal tower becomes indispensable.

  Steam is produced by utilizing the moisture contained in the waste and the waste heat of the generator and apparatus.

  Steam is first introduced into the carbonization chamber to suppress combustion and explosion in the carbonization chamber. The higher the temperature of the steam, the better. The introduction of steam having a temperature higher than the temperature of the dry distillation chamber promotes dry distillation and measures heat recovery.

  The water in the system was preferably converted into water vapor, and the water vapor surplus in the apparatus was introduced into the emergency diffusion tower, and the draft in the tower was always secured to eliminate the need for a gas combustion air blower.

  Based on the above, the present invention is characterized in that it is a closed system that does not discharge wastewater outside the system.

Steam is produced using waste water, but these waters are preferably neutralized with caustic soda for chlorine, and solids and oil floating in the water are removed through an oil / water separator and then sent to a cooling tower. It is returned and supplied to the boiler.
It is preferable that the apparatus of the said structure comprises a gas washing tower, a caustic soda tank, a caustic soda pump, and a circulating water pump.

Waste water generator equipped with a cooling tower and a circulation pump for collecting and cooling the waste water, cooling it, and reusing it is provided with an oil-water separator that removes solids and oil in the water. Boiler water supplied from the cooling tower is preferably Is supplied to the dry distillation chamber as superheated steam having a temperature of 600 ° C. or more through secondary boilers and tertiary boilers using exhaust heat of the gas generator through a primary boiler using exhaust heat of the power generator.

  The primary boiler is provided in the exhaust line of the power generator, and the secondary and tertiary boilers are provided in the high-temperature reactor outlet gas line.

The effects of the present invention are as follows.
The water contained in the waste is recovered, and the recovered water is used to generate superheated steam using the exhaust heat of the equipment, blown to the waste and dry-distilled. Based on this superheated steam, the temperature is further raised in the high-temperature reaction chamber, The charcoal, oil, and carbonization residue (charcoal) are gasified by water gas reaction, and the air accompanying the carbonization gas is converted to CO ₂ and H ₂ O by oxidation reaction while suppressing explosion by superheated steam, This gas is dedusted and washed with alkali, and good quality gas fuel that can be used in fuel cells, gas engines, gas turbines, etc. can be recovered from waste. Residue (charcoal) can be recovered as high-quality activated carbon by water vapor activation.

  Here, as an actual example, an example with human waste sludge 400 kg / hour and moisture 30% is as follows.

  The recovered gas fuel can be used as a heat source for dry distillation and reaction of the apparatus, and when converted to electricity, most of the utility necessary for the apparatus can be provided from waste.

  Currently, good quality gas fuel can be recovered from dry distillation residue that is disposed of in landfill.

  In the case of the current mainstream incineration treatment, 10 to 20 times as much combustion air as waste 1 is required. Naturally, the combustion exhaust gas is 10 to 20 times or more than waste 1, and a huge amount of exhaust gas and dioxin due to combustion Combined with other measures, the waste gas treatment facility requires several times the cost of the incinerator body. On the other hand, the waste power generation according to the present invention is a dry distillation gasification method, and the amount of dry distillation gas is about 1/20 to 1/10 of the exhaust gas amount by the incineration method. Cost reduction can be achieved.

  Water collected from the processed water after cooling and condensing is converted into superheated steam using the exhaust heat of the equipment, and this is used as an auxiliary heat source for dry distillation to reduce the main heat source and to conduct heat of water vapor. Utilizing the good rate, the structure in which superheated steam is blown directly onto waste promotes dry distillation gasification, which is about 1/3 to 1/4 compared with the case where there is no steam at the same dry distillation temperature. Dry distillation gasification is possible in about 30 minutes, and a compact distillation chamber can be achieved.

 Furthermore, by introducing surplus water vapor into the emergency stripping tower, a draft in the emergency stripping tower is secured, and not only is the carbonized gas safely processed without being blown out of the device even in an emergency, but the recovered water is completely vaporized. By using it, wastewater treatment equipment is no longer needed.

First, a waste power generation apparatus that generates power by converting waste into gas fuel according to the present invention will be described with reference to FIG.

  The waste power generation device according to the present invention is composed of three devices: a gas generation device 1 that converts waste into gas fuel, a power generation device 2 that generates power using the gas fuel, and an emergency diffusion tower 3 as a safety device. The

A gas generator 1 according to the present invention introduces a carbonization chamber 4 for carbonizing waste, a mixture of carbonization gas and water vapor coming out of the carbonization chamber, and a mixture of carbonization residue (charcoal) and water vapor coming out of the carbonization chamber, A high temperature reaction chamber 5 that gasifies charcoal and oil by gas reaction and converts the accompanying O ₂ into CO ₂ and H ₂ O by oxidation reaction, and a primary boiler 25 that produces steam using the exhaust of the generator 53. A secondary boiler 6 and a tertiary boiler 7 for superheating the water vapor, a cooling tower 8 for removing and cleaning these gases, a dust collector 9 and a gas cleaning tower 10, and an attraction for discharging the gas. A ventilator 11, a water-sealed drum 12 equipped with a gas-liquid separator for preventing backfire from the power generation device 2, an oil-water separator 16 for removing solids and oil from the wastewater, and collecting the wastewater, For cooling and reuse A ring tower 17, a water supply pump 18, a water-cooled conveyor 19 for recovering carbonization residue (charcoal), a separation device 50 for separating incombustibles and carbonization residue (charcoal), a pulverizer 20 for pulverizing the carbonization residue (charcoal), A dust collector 21 that collects pulverized carbonization residue (charcoal), a steam ejector 22 for introducing the pulverized charcoal into the high-temperature chamber, a diffusion line 23 for escaping gas safely in an emergency, an emergency release valve 24, an emergency in advance It mainly comprises a steam valve 26 for securing a draft in the stripping tower 3.

  The power generator 2 according to the present invention includes a gas storage tank 51 that stores the gas generated by the gas generator 1 and a generator 53 that generates power using the gas. A calorimeter 13, a gas flow meter 14, and a mixer 52 are provided between the gas storage tank 51 and the generator 53.

  In the emergency radiation tower 3 according to the present invention, a coil tube 27 and a pilot burner 46 for converting saturated steam into superheated steam are provided.

A waste input device 28 is provided at the inlet of the carbonization chamber 4, a dust collector 29 is provided at the gas distillation outlet, a heating tube or an electric heater 30 is provided inside the carbonization chamber 4, a steam pipe 31 having a large number of holes downward and an internal temperature. A temperature control device 32 for measuring and controlling the pressure and a pressure control device 33 for measuring and controlling the internal pressure are provided.
Inside the high temperature reaction chamber 5, a heating tube or electric heater 34, a reaction accelerator 35 and a temperature control device 36 for measuring and controlling the internal temperature are provided.

  In the lower part of the cooling tower 8, a rotary valve 37 for automatically discharging the solid content, in the cooling tower 8, a spray nozzle 38, a temperature control device 39 for measuring and controlling the exhaust gas temperature at the outlet, and this temperature control A water amount adjustment valve 40 that is opened and closed by the device is provided.

  A rotary valve 41 that automatically discharges the solid content is provided below the dust collector 9.

  The gas cleaning tower 10 is provided with a caustic soda tank 42, a caustic soda injection pump 43, a circulating water pipe 48, and a circulating water pump 44.

  At the inlet of the induction fan 11, a pressure control valve 45 that controls the pressure in the dry distillation chamber 4 is provided.

  A rotary valve 49 is provided at the outlet of the water cooling conveyor 19.

  The pulverizer 20 is provided with a nitrogen gas circulation fan 47.

 In the waste power generation apparatus configured as described above, the inside of the dry distillation chamber 4 is kept at a predetermined room temperature of 400 ° C. to 500 ° C. by a heating tube or an electric heater 30, and then the waste is continuously dry distilled by the waste input device 28. While being put into the chamber 4, superheated steam having a predetermined temperature (500 ° C. to 600 ° C.) is injected into the waste from the steam pipe 31 provided in the dry distillation chamber 4, and dry distillation is performed.

 The dry distillation gas and water vapor coming out of the dry distillation chamber 4 are introduced into the high temperature reaction chamber 5 after removing large solids and oil via the dust collector 29. The inside of the high temperature reaction chamber 5 is maintained at a predetermined temperature (900 ° C. to 1000 ° C.) by a heating tube or an electric heater 34, and the accompanying charcoal and oil are gasified by a water gas reaction with water vapor.

Further, the air that has entered the dry distillation chamber 4 and is accompanied by the dry distillation gas and water vapor is safely converted into CO ₂ and H ₂ O in the high temperature reaction chamber 5 by an oxidation reaction in an inert and large amount of water vapor atmosphere. .

  Further, the carbonization residue (charcoal) is automatically discharged by the water-cooled conveyor 19 and the rotary valve 49, and is separated into non-combustible material and carbonization residue (charcoal) by the separation device 50. The carbonization residue (charcoal) is 20 microns by the pulverizer 20. After being pulverized below, it is recovered by the dust collector 21, introduced into the high-temperature reaction chamber 5 by the steam ejector 22, and gasified by the water gas reaction in the same manner as charcoal and oil accompanying the dry distillation gas.

  The gas (including water vapor) exiting the high temperature reaction chamber 5 is kept at a predetermined temperature (200 ° C. or less below the refractory temperature of the dust collector filter cloth connected next) with water in the cooling tower 8.

  The solid content separated in the tower is discharged out of the system through a rotary valve 37 at the bottom of the tower.

  The gas exiting the cooling tower 8 is introduced into the dust collector 9, and the solid content captured here is discharged out of the system through the lower rotary valve 41. This solid content is discharged as activated carbon by steam activation in the high temperature reaction chamber.

  The gas exiting the dust collector 9 is introduced into a gas washing tower 10 and washed with caustic soda water. Hydrogen chloride (Hcl) is neutralized with caustic soda (NaOH) and returned to the cooling tower 17 together with a large amount of water as sodium chloride (Nacl). It is.

  Since the gas is cooled to about 50 ° C. by the washing water, a large amount of water in the gas is cooled and condensed and returned to the cooling tower 17 together with the Nacl. When returning to the cooling tower 17, some solids and oil accompanying the water are removed by the oil / water separator 16 and then returned to the cooling tower 17.

  The gas from which hydrogen chloride and harmful gases have been removed in the gas washing tower is introduced into the induction fan 11.

The induction fan 11 is operated at a front-rear pressure, a front pressure of −200 mmH ₂ O, and a rear pressure of 500 mmH ₂ O, and sucks out the gas from the dry distillation chamber 4 to the induction fan 11 and sends it to the power generation device 2.

  In front of the induction fan 11, a pressure control valve 45 for controlling the gas discharge amount is provided.

When the pressure in the dry distillation chamber 4 becomes positive, dry distillation gas may blow out, and when negative pressure is reached, air is drawn. Accordingly, the pressure control device 33 and the pressure control valve 45 normally maintain a slight negative pressure (± 0 to -5 mmH ₂ O) so that the seal portion in the dry distillation chamber 4 where air easily leaks is taken as a measure such as a steam seal. Controlled.

  The gas sent out by the induction fan 11 is introduced into the water sealing drum 12.

  The water seal drum 12 serves to prevent backfire from the power generation device 2 serving as an ignition source.

  The water-sealed drum 12 also has a function of a gas-liquid separator for reducing the amount of water accompanying the gas storage tank 51 as much as possible.

  At the outlet of the gas storage tank 51, a calorimeter 13, a gas flow meter 14, a gas flow control valve 15, and a mixer 52 are provided.

  Gas calorific value and gas flow rate are measured with calorimeter 13 and gas flow meter 14, respectively, and if the total calorific value is less than specified, commercially available LPG or LNG 54 is mixed with mixer 52 to obtain the specified total calorific value. Send to generator 53.

  The emergency burner tower 3 is always ignited by a pilot burner 46, and a draft is secured by surplus water vapor. The gas in an emergency is burned and safely released into the atmosphere.

  In an emergency, the emergency release valve 24 is opened, sent to the emergency radiation tower 3 by the radiation line 23, burned and safely released to the atmosphere.

  Water in the cooling tower 17 is sent to the cooling tower 8, the water cooling conveyor 19, and the primary boiler 25 by the feed pump 18, and the water sent to the cooling tower 8 is sprayed to the gas in the tower by the spray nozzle 38 at the top of the tower. The spray amount of water is controlled by the temperature control device 39 and the water amount adjusting valve 40 so that the gas outlet temperature becomes a predetermined temperature (200 ° C.). The water sent to the primary boiler 5 is sent as saturated steam to the tertiary boiler 7 via the secondary boiler 6, and as superheated steam of 500 to 600 ° C. to the steam pipe 31 equipped in the dry distillation chamber 4. Sent to the waste.

  The surplus steam was sent to the coil pipe 27 built in the emergency radiation tower by the steam flow rate control valve 26 and exhausted as high temperature superheated steam to prevent white steam.

  In addition, when the water in the cooling tower 17 is insufficient, tap water is automatically poured.

The pipe system diagram which shows the Example of this invention.

Explanation of symbols

1: Gas generator 2: Power generation device 3: Surplus gas combustion device 4: Dry distillation chamber 5: High temperature reaction chamber 6: Secondary boiler 7: Tertiary boiler 8: Cooling tower 9: Dust collector 10: Gas cleaning tower 11: Induction fan 12: Water ring drum 13: Calorimeter 14: Gas flow meter 15: Gas flow control valve 16: Oil / water separator 17: Cooling tower 18: Water supply pump 19: Water-cooled conveyor 20: Crusher 21: Dust collector 22: Steam ejector 23: Dissipation Line 24: Emergency release valve 25: Primary boiler 26: Steam flow control valve 27: Coil pipe 28: Waste input device 29: Dust collector 30: Heating pipe or electric heater 31: Steam pipe 32: Temperature control device 33: Pressure control device 34: Heating tube or electric heater 35: Reaction accelerator 36: Temperature controller 37: Rotary valve 38: Spray Nozzle 39: Temperature control device 40: Water flow control valve 41: Rotary valve 42: Caustic soda tank 43: Caustic soda injection pump 44: Circulating water pump 45: Pressure regulating valve 46: Pilot burner 47: Circulating fan 48: Circulating water piping 49: Rotary Valve 50: Sorting device
51: Gas storage tank 52: Mixer 53: Generator 54: LPG or LNG

Claims (7)

A process of recovering moisture from waste by cooling and condensing, using the recovered water as superheated steam using the waste heat of the device, spraying this to waste and dry distillation;
Carbonization gas and carbonization residue (charcoal) containing superheated steam generated by this process and superheated steam are introduced into the high-temperature reaction chamber, and the charcoal, oil and pulverized carbonization residue accompanying the carbonization gas are further heated, and water gas reaction is performed. A process of gasifying and suppressing the explosion reaction of air entrained in the dry distillation gas in an inert atmosphere of water vapor and converting it into CO ₂ and H ₂ O by an oxidation reaction;
In addition, this gas is dust-removed and washed with alkali to remove hydrogen chloride and other harmful gases and convert it to gas fuel,
A process of generating electricity using this gas fuel,
A power generation method using waste comprising   The power generation method using waste according to claim 1, wherein the gas fuel generated in the step according to claim 1 is used as a heat source for dry distillation and reaction in a high temperature reaction chamber.   Electricity generation using the gas fuel generated in the process according to claim 1, and using the electricity obtained therefrom as a heat source for dry distillation and reaction in a high-temperature reaction chamber, power generation using waste according to claim 1 or 2 Method   The main heat source is saved by recovering moisture from the waste, using the recovered water as superheated steam using the exhaust heat of the apparatus, and introducing this steam into the dry distillation chamber as an auxiliary heat source for dry distillation. A power generation method using the waste according to any one of 3 to 3.   The waste according to claim 1, wherein superheated steam used for dry distillation and generated dry distillation gas are introduced into a high-temperature reaction chamber, reheated, and entrained charcoal and oil are gasified by water gas reaction to use this gas as power generation fuel. Power generation method.   The power generation method using waste according to claim 1, wherein the carbonization residue (charcoal) is pulverized, introduced into a high-temperature reaction chamber together with superheated steam, reheated and gasified by a water gas reaction, and this gas is used as power generation fuel. Introduce a carbonization chamber that distills waste, a mixture of carbonization gas and water vapor coming out of the carbonization chamber, and a mixture of carbonization residue (charcoal) and water vapor coming out of the carbonization chamber, and gasify charcoal and oil by water gas reaction. And a gas generator comprising a high-temperature reaction chamber that converts O ₂ accompanying the reaction into CO ₂ and H ₂ O by an oxidation reaction, a boiler that produces and superheats steam using the exhaust of the generator, and a gas generator. Power generation device using waste comprising a power generation device that generates electric power using the gas fuel and an emergency radiation tower as a safety device.

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